Unearthed, Greenpeace's investigative unit, discovered that the agency has shed the equivalent of more than 2,500 full time jobs - 20 per cent of its workforce - since 2013, and hugely scaled back environmental checks on farms, industrial sites and water courses.

Last year there were nearly 5,000 fewer annual site inspections by EA officers than in 2014, the year when the agency first started recording data in its current form.

In addition, the investigation found there were close to 500 fewer ‘audits’ - in-depth inspections - per year, more than a hundred fewer checks of pollution monitoring equipment, and 2,000 fewer reviews of data submissions.

Yet recent tests by Greenpeace in the River Otter and River Tale in Devon found 29 different pesticides - some of them banned - and four antibiotics.

“Things are getting worse and compliance is getting worse, particularly in the agricultural sector. We’re getting to a point of lawlessness out there,” said Mark Lloyd, Chief Executive, of The Angling Trust.

“It’s the death of rivers by a thousands cuts. All these little trickles of pollution coming out of fields, slurry stores and farmyards add up to a giant flood of pollution which is killing our rivers slowly but surely.

“The Environment Agency used to be able to visit about one per cent of farms in a year, which was bad enough, but the cuts have reduced their resources by half, so the average farmer can expect a visit every 200 years. Many farmers will never see the Environment Agency on their farm.”

Environmental organisations claim the agency’s reduced capacity means its staff can now only investigate the most severe pollution incidents and there has also been a 40 per cent drop since 2013 in the annual number of water pollution samples taken per year by the EA.

Arlin Rickard, chief executive of the Rivers Trust, which helps the EA police England’s waterways, said: “If you ring the hotline and report a pollution incident, the Environment Agency are unlikely to come and visit unless there are dead fish.

“Local communities are having to take things into their own hands.”

The fall in monitoring comes at a time when only 14 per cent of the rivers in England are classed as having ‘good ecological status’, down from 27 per cent in 2010, which is having a knock on effect on wildlife.

Salmon, is now classed ‘at risk’ or ‘probably at risk’ in 40 of the 42 principal salmon rivers in the country, though the EA notes that the struggles of salmon are global and partly a consequence of climate change.

Salmon are now listed as 'at risk' in 40 of the 42 principal salmon rivers in the countryCredit:
Charlotte Graham

The fall in inspections is mirrored in the number of recorded breaches, with nearly 5,000 fewer infringements recorded than five years ago and the number of prosecutions dropping from 269 in 2013 to 150 in 2017 and and just 33 in the first half of this year.

“I am afraid that it gives a green light to those defiling air and water cleanliness. It is essential that Government acts quickly, firmly and vocally to dispel the appearance that they are turning a blind eye to people ruining our environment.”

Responding the findings The EA said that over the past year it had reduced serious pollution incidents to their lowest level since 2011.

An Environment Agency spokesman said: “Every day we successfully manage a wide range of challenges, such as protecting people and property from flooding, improving the nation’s water quality and responding to pollution incidents, to keep our communities safe across the country.

“Over the course of the past year the Environment Agency has reduced the number of serious pollution incidents to their lowest levels since 2011, responded to more than three times the usual number of incidents during this summer’s prolonged dry weather, enhanced over 2,000km of river habitats, created over 1,500 acres of new habitat for wildlife, and built flood defences to protect over 45,000 additional homes from flooding.”

The Rural Payments Agency, the body responsible for paying English farm subsidies, and checking compliance with environmental requirements has also cut inspections from more than 21,000 five years ago to 17,416 last year.